U.S. patent number 8,241,450 [Application Number 11/957,633] was granted by the patent office on 2012-08-14 for method for inflating a fluid-filled chamber.
This patent grant is currently assigned to Nike, Inc.. Invention is credited to William A. Brunais, Stuart C. Forstrom, Shaun J. Hensley.
United States Patent |
8,241,450 |
Hensley , et al. |
August 14, 2012 |
Method for inflating a fluid-filled chamber
Abstract
A method of manufacturing a fluid-filled chamber may include
utilizing one of a blowmolding and a thermoforming process to
define a first surface, a second surface, and a sidewall surface of
the chamber. An aperture is defined through the first surface in a
location where the first surface is spaced from the second surface.
A pressurization apparatus is located adjacent to the first surface
and around the aperture, and the pressurization apparatus is
utilized to inject a fluid into the chamber through the aperture,
compress the first surface against the second surface, and form a
bond around the aperture and between the first surface and the
second surface.
Inventors: |
Hensley; Shaun J. (Portland,
OR), Forstrom; Stuart C. (Beaverton, OR), Brunais;
William A. (Hillsboro, OR) |
Assignee: |
Nike, Inc. (Beaverton,
OR)
|
Family
ID: |
40418883 |
Appl.
No.: |
11/957,633 |
Filed: |
December 17, 2007 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20090151195 A1 |
Jun 18, 2009 |
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Current U.S.
Class: |
156/145; 156/147;
156/275.1; 156/253; 156/261; 156/252; 156/146; 156/292 |
Current CPC
Class: |
A43B
13/20 (20130101); B29D 35/122 (20130101); B29C
49/0047 (20130101); B29C 2791/007 (20130101); Y10T
156/107 (20150115); Y10T 156/1057 (20150115); B29B
2911/14326 (20130101); B29C 2791/006 (20130101); Y10T
156/1056 (20150115); B29L 2031/504 (20130101) |
Current International
Class: |
A63B
39/00 (20060101); A63B 41/00 (20060101); B29C
65/00 (20060101); B32B 38/04 (20060101); B32B
37/00 (20060101) |
Field of
Search: |
;156/145-147,253,261,292,275.1,252 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
International Search Report and Written Opinion in PCT Application
No. PCT/US2008/079078, mailed Mar. 25, 2009. cited by
other.
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Primary Examiner: Schatz; Christopher
Assistant Examiner: Hoover; Matthew
Attorney, Agent or Firm: Plumsea Law Group, LLC
Claims
The invention claimed is:
1. A method of manufacturing an article of footwear including an
upper with a void for receiving a foot of a wearer of the article
of footwear and a sole structure having a ground engaging surface,
the method comprising: forming a chamber to include a first
surface, an opposite second surface, and a sidewall surface
extending between the first surface and the second surface;
defining a depression in the first surface and the second surface,
the depression being spaced inward from the sidewall surface, and
the depression being located between lateral subchamber portions;
shaping the lateral subchamber portions to extend upwards in a
direction towards the upper to a greater extent than the depression
and to extend downwards in a direction towards the ground engaging
surface to a greater extent than the depression; defining an
aperture in the first surface and in the depression, the aperture
being within the depression; locating a pressurization apparatus
adjacent to the first surface and around the aperture; utilizing
the pressurization apparatus to (a) inject a fluid into the chamber
through the aperture, (b) compress the first surface against the
second surface, and (c) form a bond around the aperture and between
the first surface and the second surface; and incorporating the
chamber into a sole structure of the article of footwear.
2. The method recited in claim 1, wherein the step of forming the
chamber includes defining a depression in the first surface, and
the step of utilizing the pressurization apparatus includes forming
the bond at a location corresponding with the depression.
3. The method recited in claim 1, wherein the step of utilizing the
pressurization apparatus includes forming the bond with radio
frequency energy.
4. A method of manufacturing an article of footwear including an
upper with a void for receiving a foot of a wearer of the article
of footwear and a sole structure having a ground engaging surface,
the method comprising: forming a chamber to include a first
surface, a second surface, and a sidewall surface, the first
surface being opposite the second surface, and the sidewall surface
extending between the first surface and the second surface; forming
a depression in the first surface and in an area of the first
surface that is spaced inward from the sidewall surface; locating a
pressurization apparatus adjacent to the first surface and at a
location (a) where the first surface is spaced from the second
surface and (b) spaced inward from the sidewall surface; utilizing
the pressurization apparatus to (a) define an aperture through the
first surface, (b) inject a fluid into the chamber through the
aperture to pressurize an interior of the chamber, (c) compress the
first surface against the second surface, and (d) form a bond
around the aperture and between the first surface and the second
surface; and incorporating the chamber into the sole structure,
wherein one of the first surface and the second surface is oriented
to face the upper and another of the first surface and the second
surface is oriented to place the ground engaging surface.
5. The method recited in claim 4, wherein the step of utilizing the
pressurization apparatus includes forming the bond with radio
frequency energy.
6. The method recited in claim 4, further including a step of
incorporating the chamber into the sole structure of the article of
footwear.
7. A method of manufacturing an article of footwear including an
upper with a void for receiving a foot of a wearer of the article
of footwear and a sole structure having a ground engaging surface,
the method comprising: forming a chamber to include (a) a first
surface and (b) an opposite second surface; defining a depression
in the first surface and the second surface, the depression being
spaced inward from a sidewall surface of the chamber, and the
depression being located between lateral subchamber portions;
shaping the lateral subchamber portions to extend upwards in a
direction towards the upper to a greater extent than the depression
and to extend downwards in a direction towards the ground engaging
surface to a greater extent than the depression; defining an
aperture in the first and in the depression; utilizing a
pressurization apparatus to (a) inject a fluid into the chamber
through the aperture, (b) compress the first surface against the
second surface, and (c) form a bond around the aperture and between
the first surface and the second surface, and at a location
corresponding with the depression; and incorporating the chamber
into a sole structure of the article of footwear, wherein the first
surface and the second surface are unbonded to each other and are
spaced from each other in a portion of the chamber extending
entirely around the bond.
8. The method recited in claim 7, wherein the step of forming the
chamber includes defining an interior subchamber which includes the
subchamber portions, and defining the depression in the interior
subchamber.
9. The method recited in claim 7, wherein the step of utilizing the
pressurization apparatus includes forming the bond with radio
frequency energy.
10. The method recited in claim 7, wherein the step of forming the
chamber includes (a) defining a sidewall surface that extends
between the first surface and the second surface and (b) locating
the aperture at a position that is spaced from the sidewall
surface.
11. A method of manufacturing an article of footwear including an
upper with a void for receiving a foot of a wearer of the article
of footwear and a sole structure having a ground engaging surface,
the method comprising: forming a chamber including a first surface,
an opposite second surface, and a sidewall surface extending
between the first surface and the second surface, the sidewall
surface having a lateral portion and a medial portion, a portion of
the first surface and a portion of the second surface forming an
inflation area between the lateral portion of the sidewall and the
medial portion of the sidewall, the inflation area being spaced
inward from the lateral portion and being spaced inward from the
medial portion; forming a depression in the first surface and in an
area of the first surface that is spaced inward from the sidewall
surface; defining an aperture in the first surface in the
depression at the inflation area; utilizing a pressurization
apparatus to (a) inject a fluid into the chamber through the
aperture, (b) compress the first surface against the second surface
in the inflation area, and (c) form a bond between the first
surface and the second surface at the inflation area and around the
aperture; incorporating the chamber into a sole structure of the
article of footwear, wherein one of the first surface and the
second surface is oriented to face the upper and another of the
first surface and the second surface is oriented to face the ground
engaging surface.
12. The method recited in claim 11, wherein the step of forming the
chamber includes forming a subchamber, and the step of defining the
aperture includes locating the aperture at the subchamber.
13. The method recited in claim 12, wherein the subchamber is an
interior subchamber.
14. The method recited in claim 13, wherein the step of forming the
chamber further includes forming a peripheral subchamber, and the
interior subchamber is centrally-located in the chamber.
Description
BACKGROUND
Articles of footwear generally include two primary elements, an
upper and a sole structure. The upper is formed from a variety of
material elements (e.g., textiles, foam, leather, and synthetic
leather) that are stitched or adhesively bonded together to form a
void on the interior of the footwear for comfortably and securely
receiving a foot. An ankle opening through the material elements
provides access to the void, thereby facilitating entry and removal
of the foot from the void. In addition, a lace is utilized to
modify the dimensions of the void and secure the foot within the
void.
The sole structure is located adjacent to a lower portion of the
upper and is generally positioned between the foot and the ground.
In many articles of footwear, including athletic footwear, the sole
structure conventionally incorporates an insole, a midsole, and an
outsole. The insole is a thin compressible member located within
the void and adjacent to a lower surface of the void to enhance
footwear comfort. The midsole, which may be secured to a lower
surface of the upper and extends downward from the upper, forms a
middle layer of the sole structure. In addition to attenuating
ground reaction forces (i.e., providing cushioning for the foot),
the midsole may limit foot motions or impart stability, for
example. The outsole, which may be secured to a lower surface of
the midsole, forms the ground-contacting portion of the footwear
and is usually fashioned from a durable and wear-resistant material
that includes texturing to improve traction.
The conventional midsole is primarily formed from a foamed polymer
material, such as polyurethane or ethylvinylacetate, that extends
throughout a length and width of the footwear. In some articles of
footwear, the midsole may include a variety of additional footwear
elements that enhance the comfort or performance of the footwear,
including plates, moderators, fluid-filled chambers, lasting
elements, or motion control members. In some configurations, any of
these additional footwear elements may be located between the
midsole and either of the upper and outsole, embedded within the
midsole, or encapsulated by the foamed polymer material of the
midsole, for example. Although many conventional midsoles are
primarily formed from a foamed polymer material, fluid-filled
chambers or other non-foam structures may form a majority of some
midsole configurations.
Various techniques may be utilized to form fluid-filled chambers
for articles of footwear or other products, including a two-film
technique, a thermoforming technique, and a blowmolding technique,
for example. In the two-film technique, two separate polymer sheets
are bonded together at specific locations. The thermoforming
technique is similar to the two-film technique in that two polymer
sheets are bonded together, but also includes utilizing a heated
mold to form or otherwise shape the polymer sheets. In the
blow-molding technique, a parison formed from a molten or otherwise
softened polymer material is placed within a mold having a cavity
with the desired configuration of the chamber. Pressurized air
induces the polymer material to conform with surfaces of the
chamber. The polymer material then cools and retains the shape of
the cavity, thereby forming the chamber.
Following each of the techniques discussed above, the chambers are
pressurized. That is, a pressurized fluid is injected into the
chambers and then sealed within the chambers. One method of
pressurization involves forming inflation conduits in residual
portions of the polymer sheets or the parison. In order to
pressurize the chambers, the fluid is injected through the
inflation conduits, which are then sealed. The residual portions of
the polymer sheets or the parison, including the inflation
conduits, are then trimmed or otherwise removed to substantially
complete manufacture of the chambers.
SUMMARY
An article of footwear is disclosed below as having an upper and a
sole structure secured to the upper. The sole structure includes a
fluid-filled chamber with an upper surface, an opposite lower
surface, and a sidewall surface extending between the upper surface
and the lower surface. The chamber has an inflation area that
defines an aperture extending through one of the upper surface and
the lower surface. The upper surface and the lower surface are
bonded to each other in the inflation area and around the
aperture.
A method of manufacturing a fluid-filled chamber is also disclosed
below. The method includes defining a first surface, a second
surface, and a sidewall surface of the chamber. An aperture is
defined through the first surface in a location where the first
surface is spaced from the second surface. A pressurization
apparatus is located adjacent to the first surface and around the
aperture, and the pressurization apparatus is utilized to inject a
fluid into the chamber through the aperture. The first surface is
then compressed against the second surface, and a bond is formed
around the aperture and between the first surface and the second
surface.
The advantages and features of novelty characterizing aspects of
the invention are pointed out with particularity in the appended
claims. To gain an improved understanding of the advantages and
features of novelty, however, reference may be made to the
following descriptive matter and accompanying figures that describe
and illustrate various configurations and concepts related to the
invention.
FIGURE DESCRIPTIONS
The foregoing Summary and the following Detailed Description will
be better understood when read in conjunction with the accompanying
figures.
FIG. 1 is a lateral side elevational view of an article of
footwear.
FIG. 2 is a medial side elevational view of the article of
footwear.
FIG. 3 is a perspective view of a sole structure of the
footwear.
FIG. 4 is an exploded perspective view of the sole structure.
FIG. 5 is a perspective view of a fluid-filled chamber of the sole
structure.
FIG. 6 is a top plan view of the chamber.
FIG. 7A-7D are cross-sectional views of the chamber, as defined by
section lines 7A-7D in FIG. 6.
FIGS. 8A-8B are perspective views of a mold for manufacturing the
chamber.
FIGS. 9A-9C are side elevational views of the mold depicting a
blowmolding process for the chamber.
FIG. 10 is a perspective view of the chamber and residual polymer
material following the blowmolding process.
FIG. 11 is a perspective view of the chamber following removal of
the residual polymer material.
FIGS. 12A-12D are cross-sectional views of the chamber, as defined
by section lines 12A-12D in FIG. 11.
FIGS. 13A and 13B are schematic perspective views of an inflation
apparatus.
FIGS. 14A-14F are schematic cross-sectional views depicting an
inflation process for the chamber.
FIG. 15 is a side elevational view of another configuration of the
inflation apparatus.
FIG. 16 is a perspective view of another configuration of the
mold.
FIG. 17 is a perspective view of a chamber formed from the mold
configuration depicted in FIG. 16.
FIGS. 18A and 18B are schematic perspective views of another
configuration of the inflation apparatus.
FIGS. 19A-19D are top plan views depicting further configurations
of the chamber.
FIGS. 20A-20C are a top plan views of additional chambers.
DETAILED DESCRIPTION
The following discussion and accompanying figures disclose various
configurations of fluid-filled chambers and methods for
manufacturing the chambers. Although the chambers are disclosed
with reference to footwear having a configuration that is suitable
for running, concepts associated with the chambers may be applied
to a wide range of athletic footwear styles, including basketball
shoes, cross-training shoes, football shoes, golf shoes, hiking
shoes and boots, ski and snowboarding boots, soccer shoes, tennis
shoes, and walking shoes, for example. Concepts associated with the
chambers may also be utilized with footwear styles that are
generally considered to be non-athletic, including dress shoes,
loafers, and sandals. In addition to footwear, the chambers may be
incorporated into other types of apparel and athletic equipment,
including helmets, gloves, and protective padding for sports such
as football and hockey. Similar chambers may also be incorporated
into cushions and other compressible structures utilized in
household goods and industrial products. Accordingly, chambers
incorporating the concepts disclosed herein may be utilized with a
variety of products.
General Footwear Structure
An article of footwear 10 is depicted in FIGS. 1 and 2 as including
an upper 20 and a sole structure 30. For reference purposes,
footwear 10 may be divided into three general regions: a forefoot
region 11, a midfoot region 12, and a heel region 13, as shown in
FIGS. 1 and 2. Footwear 10 also includes a lateral side 14 and a
medial side 15. Forefoot region 11 generally includes portions of
footwear 10 corresponding with the toes and the joints connecting
the metatarsals with the phalanges. Midfoot region 12 generally
includes portions of footwear 10 corresponding with the arch area
of the foot, and heel region 13 corresponds with rear portions of
the foot, including the calcaneus bone. Lateral side 14 and medial
side 15 extend through each of regions 11-13 and correspond with
opposite sides of footwear 10. Regions 11-13 and sides 14-15 are
not intended to demarcate precise areas of footwear 10. Rather,
regions 11-13 and sides 14-15 are intended to represent general
areas of footwear 10 to aid in the following discussion. In
addition to footwear 10, regions 11-13 and sides 14-15 may also be
applied to upper 20, sole structure 30, and individual elements
thereof.
Upper 20 is depicted as having a substantially conventional
configuration incorporating a plurality material elements (e.g.,
textile, foam, leather, and synthetic leather) that are stitched or
adhesively bonded together to form an interior void for securely
and comfortably receiving a foot. The material elements may be
selected and located with respect to upper 20 in order to
selectively impart properties of durability, air-permeability,
wear-resistance, flexibility, and comfort, for example. An ankle
opening 21 in heel region 13 provides access to the interior void.
In addition, upper 20 may include a lace 22 that is utilized in a
conventional manner to modify the dimensions of the interior void,
thereby securing the foot within the interior void and facilitating
entry and removal of the foot from the interior void. Lace 22 may
extend through apertures in upper 20, and a tongue portion of upper
20 may extend between the interior void and lace 22. Given that
various aspects of the present application primarily relate to sole
structure 30, upper 20 may exhibit the general configuration
discussed above or the general configuration of practically any
other conventional or non-conventional upper. Accordingly, the
overall structure of upper 20 may vary significantly.
Sole structure 30 is secured to upper 20 and has a configuration
that extends between upper 20 and the ground. In effect, therefore,
sole structure 30 is located to extend between the foot and the
ground. In addition to attenuating ground reaction forces (i.e.,
providing cushioning for the foot), sole structure 30 may provide
traction, impart stability, and limit various foot motions, such as
pronation. The primary elements of sole structure 30 are a plate
40, a chamber 50, and an outsole 60, as depicted in FIGS. 3 and 4.
Plate 40 forms an upper portion of sole structure 30 and is
positioned adjacent to upper 20. Chamber 50 forms a middle portion
of sole structure 30 and is positioned between plate 40 and outsole
60. In addition, outsole 60 forms a lower portion of sole structure
30 and is positioned to engage the ground. Each of plate 40,
chamber 50, and outsole 60 extend around a perimeter of sole
structure 30 and have a shape that generally corresponds with an
outline of the foot. More particularly, plate 40, chamber 50, and
outsole 60 extend from forefoot region 11 to heel region 13 and
also from lateral side 14 to medial side 15. Accordingly, each of
plate 40, chamber 50, and outsole 60 are exposed to an exterior of
footwear 10 and cooperatively form a side surface of sole structure
30.
Chamber Configuration
Chamber 50, which is depicted individually in FIGS. 5-7D, is formed
from a polymer material that provides a sealed barrier for
enclosing a fluid. The polymer material defines an upper surface
51, an opposite lower surface 52, and a sidewall surface 53 that
extends around a periphery of chamber 50 and between surfaces 51
and 52. As discussed above, chamber 50 has a shape that generally
corresponds with an outline of the foot. As with plate 40 and
outsole 60, chamber 50 is exposed to an exterior of footwear 10 and
forms a portion of the side surface of sole structure 30. More
particularly, sidewall surface 53 is exposed to the exterior of
footwear 10 around substantially all of the side surface of sole
structure 30.
Chamber 50 includes various bonded areas 54 where upper surface 51
is bonded or otherwise joined to lower surface 52. In general,
bonded areas 54 are spaced inward from sidewall surface 53 and form
various depressions or indentations in each of surfaces 51 and 52.
Some of the depressions in upper surface 51 are shaped to receive
various projections that extend downward from plate 40. That is,
the projections of plate 40 extend into the depressions formed by
portions of bonded areas 54. Similarly, some of the depressions in
lower surface 52 are shaped to receive various projections that
extend upward from outsole 60. That is, the projections of outsole
60 also extend into the depressions formed by portions of bonded
areas 54.
Bonded areas 54 also form various subchambers within chamber 50.
For example, a peripheral subchamber 55 extends around the
periphery of chamber 50 and a plurality of interior subchambers 56
are centrally-located in chamber 50. Various conduits may connect
subchambers 55 and 56 such that the fluid within chamber 50 may
pass between subchambers 55 and 56. In some configurations, the
conduits may be absent or sealed to prevent fluid transfer between
subchambers 55 and 56. When the conduits are absent or sealed, the
fluid within subchambers 55 and 56 may be pressurized to different
degrees.
In addition to bonded areas 54, an inflation area 57 has a
configuration wherein upper surface 51 is bonded or otherwise
joined to lower surface 52. Inflation area 57 is spaced inward from
sidewall surface 53. More particularly, inflation area 57 is
located in midfoot region 12, centered between sides 14 and 15, and
extends through a center of one of interior subchambers 56. As
described in greater detail below, chamber 50 is inflated through
inflation area 57 and has the advantages of (a) imparting a clean,
relatively unbroken appearance to sidewall surface 53, (b) reducing
the quantity of residual polymer material produced during the
manufacturing process, and (c) decreasing the size of a mold that
is utilized during the manufacturing process.
The fluid within chamber 50 may range in pressure from zero to
three-hundred-fifty kilopascals (i.e., approximately fifty-one
pounds per square inch) or more. In addition to air and nitrogen,
the fluid contained by chamber 50 may include octafluorapropane or
be any of the gasses disclosed in U.S. Pat. No. 4,340,626 to Rudy,
such as hexafluoroethane and sulfur hexafluoride, for example. In
some configurations, chamber 50 may incorporate a valve that
permits the individual to adjust the pressure of the fluid. In
other configurations, chamber 50 may be incorporated into a fluid
system, as disclosed in U.S. Pat. No. 7,210,249 to Passke, et al.,
as either a pump chamber or a pressure chamber.
A variety of polymer materials may be utilized for chamber 50. In
selecting a polymer material for chamber 50, engineering properties
of the polymer material (e.g., tensile strength, stretch
properties, fatigue characteristics, dynamic modulus, and loss
tangent) as well as the ability of the material to limit the
diffusion of the fluid contained by chamber 50 may be considered.
When formed of thermoplastic urethane, for example, the polymer
material of chamber 50 may have a thickness of approximately 0.89
millimeter, but the thickness may range from 0.25 to 4.0
millimeters or more, for example. In addition to thermoplastic
urethane, examples of polymer materials that may be suitable for
chamber 50 include polyurethane, polyester, polyester polyurethane,
polyether polyurethane, and polyurethane including a polyester
polyol. Accordingly, a variety of polymer materials may be utilized
for chamber 50.
In manufacturing chamber 50, both a molding process and an
inflation process are utilized. The molding process involves
shaping a polymer material to define the general configuration of
chamber 50. More particularly, the molding process includes shaping
the polymer material to form surfaces 51-53 and also form bonded
areas 54 to define subchambers 55 and 56. Although not performed
during some molding processes, a portion of inflation area 57 may
also be formed or otherwise defined. Once the molding process is
complete, the inflation process is utilized to pressurize and seal
chamber 50.
Molding Process
A variety of molding process may be suitable for chamber 50,
including a blowmolding process. Referring to FIGS. 8A and 8B, a
mold 60 has a first mold portion 61 and a second mold portion 62.
Each of mold portions 61 and 62 cooperatively define an internal
cavity 63 with the configuration of chamber 50. When mold portions
61 and 62 are joined together, therefore, cavity 63 has dimensions
substantially corresponding with the exterior dimensions of chamber
50 in an unpressurized state. In other configurations, mold
portions 61 and 62 may cooperatively define two internal cavities
63, one having the configuration of chamber 50, which is suitable
for footwear 10 when configured for the right foot of the
individual, and the other having the configuration of a mirror
image of chamber 50, which is suitable for footwear 10 when
configured for the left foot of the individual.
The manner in which mold 60 is utilized to form chamber 50 from a
polymer material will now be discussed in greater detail.
Initially, a parison 64 is located between mold portions 61 and 62,
as depicted in FIG. 9A. Parison 64 is formed from a molten,
semi-molten, or at least partially uncured polymer material having
a tubular configuration. Although parison 64 may have a circular
cross-section, parison 64 may also be formed to have an elliptical
or otherwise elongate cross-section. Although a wall thickness of
parison 64 may be uniform, some areas of parison 64 may have
different thicknesses to accommodate the forming of chamber 50.
Once parison 64 is properly located between mold portions 61 and
62, mold 60 closes such that the polymer material of parison 64
enters cavity 63 and is shaped to conform with cavity 63, as
depicted in FIG. 9B. That is, mold portions 61 and 62 translate
toward each other to close upon parison 64 and draw the polymer
material of parison 64 into cavity 63. As mold 60 contacts parison
64, air or another fluid having a positive pressure in comparison
with ambient air may be injected into a hollow, central area of
parison 64 to induce the polymer material to contact and conform to
the contours of mold portions 61 and 62. Air may also be removed
from the area between parison 64 and mold portions 61 and 62
through various vents, thereby drawing the polymer material of
parison 64 onto the surfaces of cavity 63. That is, at least a
partial vacuum may be formed between an exterior of parison 64 and
the surfaces of mold portions 61 and 62. As the area within parison
64 is pressurized and air is removed from the area between parison
64 and mold 60, the polymer material is drawn against and conforms
with the surfaces of mold 60. More specifically, the polymer
material of parison 64 stretches, bends, or otherwise conforms to
extend along the surfaces of cavities 63 within mold 60 and form
the general shape of chamber 50. In addition to being shaped,
opposite sides of parison 64 are bonded to each other in various
locations. More particularly, mold portions 61 and 62 compress
opposite sides of parison 64 together at (a) a location
corresponding with sidewall surface 63 and (b) at locations
corresponding with the various bonded areas 54.
A parting line is formed where the opposite sides of parison 64 are
bonded together along sidewall surface 63. The parting line is,
therefore, an area of chamber 50 where opposite sides of parison 64
are bonded together. Although the parting line may extend along a
center of sidewall surface 53 (i.e., located between and spaced
equally from surfaces 51 and 62), the parting line may also be
located at an interface between sidewall surface 53 and either of
surfaces 51 and 52. In some configurations, the parting line may
also be located at the interface between sidewall surface 53 and
upper surface 51 in a portion of chamber 50, and located at the
interface between sidewall surface 53 and lower surface 52 in
another portion of chamber 50. Accordingly, the location of the
parting line may vary significantly.
Once chamber 50 is formed within mold 60, mold portions 61 and 62
separate such that chamber 50 and residual portions of parison 64
may be removed from mold 60, as depicted in FIGS. 9C and 10.
Chamber 50 is then permitted to cool, and the residual portions of
parison 64 are detached, as depicted in FIG. 11. When formed from a
thermoplastic polymer, for example, the residual portions may be
recycled and utilized in other chambers. At this stage of
manufacturing, chamber 50 is substantially formed to exhibit the
configuration depicted in FIGS. 5-7D, but is substantially
unpressurized. FIGS. 12A-12D depict various cross-sections through
chamber 50 following removal from mold 60. In comparing FIGS.
12A-12D with corresponding FIGS. 7A-7D, surfaces 51-53 bulge
outward to a lesser degree due to the unpressurized fluid within
chamber 50. A further difference between FIGS. 12A-12D and FIGS.
7A-7D relates to inflation area 57. Whereas the portions surfaces
51 and 52 that form inflation area 57 are bonded together in FIGS.
7B and 7D, the portions of surfaces 51 and 52 that form inflation
area 57 are unbonded and spaced from each other in FIGS. 12B and
12D. Although mold 60 formed depressions in each of surfaces 51 and
52 at inflation area 57, the depressions are spaced from each other
and unbonded to each other. In some configurations, mold 60 may
form an inflation area 57 wherein depressions are absent in
surfaces 51 and 52.
An alternative to the blowmolding process discussed above, a
thermoforming process may be utilized to form chamber 50. Whereas
parison 64 is utilized in the blowmolding process, two sheets of
thermoplastic polymer material are utilized in the thermoforming
process. In general, the sheets are heated and placed between mold
portions 61 and 62. Mold 60 then closes upon the sheets such that
the sheets are drawn into cavity 63 and against the contours of the
mold. Either or both of a vacuum on the exterior of the sheets and
pressure between the sheets may be used to ensure that the sheets
contact the surfaces of cavity 63. As with the blowmolding process,
the mold shapes the sheets and forms bonded areas 54. Upon removal
from mold 60, chamber 50 (when formed from the thermoforming
process) is substantially unpressurized, but has the general shape
of chamber 50 when pressurized. More particularly, each of surfaces
51 and 52 are contoured to have the general contours of chamber 50
in the pressurized state, and the interior of chamber 50 defines
air or fluid spaces wherein surfaces 51 and 52 are spaced from each
other. In inflation area 57, for example, surfaces 51 and 52 are
spaced from each other to form an air or fluid gap between surfaces
51 and 52.
Inflation Process
Following the molding process, chamber 50 is pressurized through
the inflation process. An inflation apparatus 70 is schematically
depicted in FIGS. 13A and 13B as including a punch 71, a die 72,
and a platen 73. Whereas the position of platen 73 may remain
fixed, punch 71 and die 72 are mechanically-configured to
individually translate toward platen 73 and away from platen 73. As
described in greater detail below, one or more chambers 50 may be
located on platen 73, and punch 71 is utilized to form an aperture
in either of surfaces 51 and 52 at inflation area 57. Die 72 then
contacts inflation area 57 and a fluid is injected into chamber 50
through the aperture. Once chamber 50 is pressurized with the
fluid, die 72 compresses surfaces 51 and 52 together and forms a
bond at inflation area 57 and around the aperture to effectively
seal the pressurized fluid within chamber 50. Accordingly, die 72
may be utilized to both pressurize and bond chamber 50.
The inflation process will now be discussed in greater detail.
Referring to FIG. 14A, chamber 50 is depicted as being located upon
platen 73 and punch 71 is positioned above inflation area 57.
Although chamber 50 is substantially unpressurized at this stage of
manufacturing, air or another fluid is sealed within chamber 50.
Punch 71 then translates or otherwise moves downward and pierces
upper surface 51 in inflation area 57 to form an aperture 58, as
depicted in FIG. 14B. Although punch 71 is depicted as piercing
upper surface 51, punch 71 may also pierce lower surface 52 or both
of surfaces 51 and 52.
Once aperture 58 is formed, thereby proving a means for introducing
the pressurized fluid, die 72 is positioned above inflation area
57, as depicted in FIG. 14C. As depicted in FIG. 13A, punch 71 is
associated with one area of platen 73, and die 72 is associated
with another area of platen 73. Accordingly, chamber 50 may be
moved from the area of punch 71 to the area of die 72 to position
die 72 above inflation area 57. In other configurations, die 72 may
change positions with punch 71 such that chamber 50 may remain in
one position throughout the inflation process. In yet other
configurations, punch 71 and die 72 may be incorporated into a
single unit in order to enhance the efficiency of the inflation
process.
Die 57 has a generally cylindrical configuration with a hollow
interior. Although not depicted, die 57 may be operatively
connected to a fluid source that releases the pressurized fluid
into the hollow interior. Once positioned, die 72 translates or
otherwise moves downward and contacts upper surface 51 in inflation
area 57 such that sidewalls of die 72 extend around aperture 58, as
depicted in FIG. 14D. At this stage, the fluid source may be used
to pressurize the hollow interior of die 57, and the pressurized
fluid passes through aperture 58 to also pressurize chamber 50. In
some inflation processes, a two-stage pressurization process may be
utilized. More particularly, an initial and relatively low
pressurization may occur to create a seal between die 72 and
inflation area 57, and then a subsequent and relatively high
pressurization may occur once the seal is created. That is, the
hollow interior of die 72 may first be pressurized at a relatively
low level to form a seal, and subsequently pressurized at a
relatively high level.
Following the pressurization of chamber 50, die 72 translates
further downward to compress upper surface 51 against lower surface
52 in inflation area 57, as depicted in FIG. 14E. Once surfaces 51
and 52 are compressed, die 72 forms a bond between surfaces 51 and
52 in inflation area 57. A variety of bonding techniques may be
utilized to form the bond around the aperture, including radio
frequency bonding, adhesive bonding, and thermobonding. If radio
frequency bonding is utilized, for example, radio frequency energy
(RF energy) may be emitted by die 72 in order to heat the polymer
material in inflation area 57. More particularly, the radio
frequency energy may pass from die 72 to plate 73, thereby passing
through inflation area 57 and heating the polymer material. Upon
cooling, die 72 may be retracted to substantially complete the
manufacture of chamber 50, as depicted in FIG. 14F.
As discussed above, die 72 has a cylindrical configuration with a
hollow interior. A lower surface of die 72 has, therefore, a
circular shape. When in contact with upper surface 51, the circular
shape extends around aperture 58 and prevents the pressurized fluid
from escaping. The circular shape also forms a circular bond that
extends around aperture 58 and effectively seals the pressurized
fluid within chamber 50.
One advantage to the inflation process relates to sidewall surface
53. In some prior chambers, an inflation conduit was formed in the
residual polymer material during the bonding process. The inflation
conduit extended outward from a sidewall of a chamber and was
utilized to direct a pressurized fluid into the chamber. Once
pressurized, the inflation conduit was sealed and trimmed adjacent
to the sidewall. When encapsulated within a polymer foam material,
the sealed inflation conduit would not be visible. In footwear 10,
however, sidewall surface 53 is exposed to the exterior of footwear
10 around substantially all of the side surface of sole structure
30. By locating inflation area 57 at an interior of chamber 50,
inflation area 57 is not visible or only minimally visible from the
side surface of sole structure 30. Accordingly, the inflation
process imparts a clean, relatively unbroken appearance to sidewall
surface 53. Although inflation area 57 is located in midfoot region
12 and centered between sides 14 and 15, inflation area 57 may also
be located in either of regions 11 and 13 and may be adjacent to or
spaced from sides 14 and 15.
Another advantage relates to the residual polymer material from
parison 64. When a chamber is formed with an inflation conduit, the
inflation conduit extends outward and into the residual polymer
material, thereby requiring that the residual polymer material have
a size that accommodates formation of the inflation conduit. By
eliminating the inflation conduit, however, the inflation process,
reduces the quantity of residual polymer material produced during
the manufacturing process. As a related advantage, the size of a
mold may be reduced given that the mold does not also form the
inflation conduit. Accordingly, the inflation process decreases the
size of a mold that is utilized during the manufacturing
process.
In comparing FIGS. 12A-12D with corresponding FIGS. 7A-7D, the
portions of surfaces 51 and 52 that form inflation area 57 are
unbonded and spaced from each other in FIGS. 12B and 12D, and the
portions surfaces 51 and 52 that form inflation area 57 are bonded
together in FIGS. 7B and 7D. By initially spacing the portions of
surfaces 51 and 52 that form inflation area 57, punch 71 may form a
single aperture in chamber 50 (e.g., through upper surface 51),
rather than apertures through both of surfaces 51 an 52. Following
the inflation process, however, the portions surfaces 51 and 52
that form inflation area 57 are bonded together in an unspaced
configuration.
The inflation process discussed above provides an example of a
suitable inflation process for chamber 50 and a variety of other
chambers. Various aspects of the inflation process may, however, be
modified to enhance efficiency or otherwise provide additional
benefits. As an example, punch 71 and die 72 may be incorporated
into a single unit, as depicted in FIG. 15, in order to enhance the
efficiency of the inflation process. More particularly, punch 71
may extend through the hollow interior of die 72. Once punch 71
forms aperture 58, punch 71 may retract to permit die 72 to
contact, pressurize, and bond chamber 50. In addition, a
substantially identical inflation process may be utilized when
chamber 50 is formed through a thermoforming process.
Molding And Inflation Process Variation
In processes discussed above, chamber 50 is formed to have a sealed
configuration, and punch 71 is subsequently used to form aperture
58. As an alternative, mold 60 may incorporate a needle 65, as
depicted in FIG. 16. During the molding process, needle 65 pierces
or otherwise extends through one side of parison 64 to form
aperture 58. Once an end of needle 65 is located within parison 64,
a fluid may be ejected from needle 65 to pressurize the interior of
parison 64, thereby inducing the polymer material to contact and
conform with the contours of mold 60. Accordingly, needle 65 may be
utilized to (a) form aperture 58 during the molding of chamber 50
and (b) assist with forming chamber 50. When chamber 50 is removed
from mold 60 and residual polymer material is trimmed as, depicted
in FIG. 17, aperture 58 is formed in inflation area 57.
Following the molding process, chamber 50 is pressurized through an
inflation process that is similar to the inflation process
discussed above. Given that aperture 58 is formed by needle 65,
however, punch 71 and the various steps associated with utilizing
punch 71 may be removed from the inflation process. Referring to
FIGS. 18A and 18B, therefore, inflation apparatus 70 is
schematically depicted as including only die 72 and platen 73.
Chamber 50, which is already formed to include aperture 58, may be
located on platen 73, and die 72 is then utilized to pressurize
chamber 50, compresses surfaces 51 and 52 together, and form the
bond at inflation area 57 and around aperture 58. Accordingly, the
steps of the inflation process that are depicted and discussed
relative to FIGS. 14C-14F are utilized.
Additional Chamber Configurations
The configuration of chamber 50 depicted above provides an example
of a suitable configuration for footwear 10. As another example,
chamber 50 may form a bond 59 between regions 13 and 14 to
segregate chamber 50 into two subchambers that each include an
inflation area 57, as depicted in FIG. 19A. In this configuration,
the portion of chamber 50 in regions 11 and 12 may be pressurized
less than the portion of chamber 50 in heel region 13. Similarly,
chamber 50 may have three inflation areas 57, as depicted in FIG.
19B, that permit different pressurizations for a peripheral area
and the two central areas in regions 11 and 13. In some
configurations, chamber 50 may be limited to forefoot region 11, as
depicted in FIG. 19C, or chamber 50 may be limited to heel region
13, as depicted in FIG. 19D.
As an alternative to plate 40 and chamber 50, footwear 10 or other
articles of footwear may incorporate a variety of other chambers.
Referring to FIG. 20A, a chamber 150 is depicted as being a
thermoformed structure that includes a peripheral area 151
extending around a periphery of chamber 150 and a plurality of
crossing areas 152 extending laterally across a width of chamber
150. As with chamber 50, peripheral area 151 may be exposed to an
exterior of an article of footwear. Accordingly, an inflation area
157 is located in a central portion of chamber 150 (i.e., in one of
crossing areas 152) to position inflation area 157 in a portion of
chamber 150 that is not visible or only minimally visible from a
side of chamber 150.
Referring to FIG. 20B, a thermoformed chamber 250 is depicted as
having a similar configuration that includes a peripheral area 251
and a plurality of crossing areas 252. In addition, chamber 250
includes a heel area 253. In order to inflate heel area 253 to a
different pressure than each of areas 251 and 252, chamber 250
includes two inflation areas 257. One of inflation areas 257 is
located in a central portion of chamber 250 (i.e., in one of
crossing areas 252) to position inflation area 257 in a portion of
chamber 250 that is not visible or only minimally visible from a
side of chamber 250. Another of inflation areas 257 is located in
heel area 253 to permit heel area 253 to have a different (e.g.,
lesser) pressure than each of areas 251 and 252. The inflation area
257 located in heel area 253 is also spaced inward from a side of
chamber 250 to position inflation area 257 in a portion of chamber
250 that is not visible or only minimally visible from a side of
chamber 250.
A further configuration of a thermoformed structure is depicted in
FIG. 20C as a chamber 350 that includes a peripheral area 351, a
central area 352, and a heel area 353. One portion of a conduit 354
extends between peripheral area 351 and central area 352, and
another portion of conduit 354 extends between central area 352 and
heel area 353. When initially formed, each of areas 351-353 may be
in fluid communication through conduit 354. Once pressurized
through an inflation area 357, however, a bond 359 is formed that
permits peripheral area 351 to be pressurized differently than
either of areas 352 and 353. More particularly, inflation apparatus
70 may be utilized at inflation area 357 to pressurize chamber 350
to a first pressure. Once pressurized, bond 359 may be formed to
retain the first pressure within areas 352 and 353. Inflation
apparatus 70 may then be utilized at inflation area 357 to
pressurize peripheral area 351 to a higher second pressure, and
then inflation apparatus 70 may bond inflation area 357 to retain
the second pressure within peripheral area 351.
Chambers 250 and 350 each include areas with different pressures.
In chamber 250, the different pressures are provided through two
different inflation areas 257. In chamber 350, however, a single
inflation area 357 (and a bond 359) is utilized to impart the
different pressures. Accordingly, inflation apparatus 70 (or
similar inflation apparatuses) may be utilized in various ways to
impart different pressures to areas of a chamber.
The invention is disclosed above and in the accompanying figures
with reference to a variety of configurations. The purpose served
by the disclosure, however, is to provide an example of the various
features and concepts related to the invention, not to limit the
scope of the invention. One skilled in the relevant art will
recognize that numerous variations and modifications may be made to
the configurations described above without departing from the scope
of the present invention, as defined by the appended claims.
* * * * *